Conjunctival UV autofluorescence – Prevalence and risk factors

PurposeAutofluorescence of ultraviolet (UV) light has been shown to occur in localised areas of the bulbar conjunctiva, which map to active cellular changes due to UV and environmental exposure. This study examined the presence of conjunctival UV autofluorescence in eye care practitioners (ECPs) across Europe and the Middle East and its associated risk factors.MethodImages were captured of 307 ECPs right eyes in the Czech Republic, Germany, Greece, Kuwait, Netherlands, Sweden, Switzerland, United Arab Emirates and the United Kingdom using a Nikon D100 camera and dual flash units through UV filters. UV autofluorescence was outlined using ImageJ software and the nasal and temporal area quantified. Subjects were required to complete a questionnaire on their demographics and lifestyle including general exposure to UV and refractive correction.ResultsAverage age of the subjects was 38.5 ± 12.2 years (range 19–68) and 39.7% were male. Sixty-two percent of eyes had some conjunctival damage as indicated by UV autofluorescence. The average area of damage was higher (p = 0.005) nasally (2.95 ± 4.52 mm²) than temporally (2.19 ± 4.17 mm²). The area of UV damage was not related to age (r = 0.03, p = 0.674), gender (p = 0.194), self-reported sun exposure lifestyle (p > 0.05), geographical location (p = 0174), sunglasses use (p > 0.05) or UV-blocking contact lens use (p > 0.05), although it was higher in those wearing contact lenses with minimal UV-blocking and no spectacles (p = 0.015). The area of UV damage was also less nasally in those who wore contact lenses and spectacles compared to those with no refractive correction use (p = 0.011 nasal; p = 0.958 temporal).ConclusionUV conjunctival damage is common even in Europe, Kuwait and UAE, and among ECPs. The area of damage appears to be linked with the use of refractive correction, with greater damage nasally than temporally which may be explained by the peripheral light focusing effect.     

Canthaxanthin in aquafeed applications: is there any risk?

The carotenoid pigment ‘canthaxanthin’ has been used in aquafeed for many years in order to impart the desired flesh colour in farmed salmonids. A side effect of extreme over-dosage of this carotenoid is the deposition of minute crystals in the eye, a fact leading to adverse media attention for canthaxanthin in the past, and some pressure to limit its use aquafeeds. A real appraisal of the possible amount of canthaxanthin ingested by humans through the consumption of notable quantities of highly pigmented salmon, reveals that it is extremely unlikely that consumers could be exposed to sufficient canthaxanthin to attain the established ADI for this pigment. Additionally, the ADI is 10 times lower than the reported no-effect level (NOEL) for canthaxanthin. Therefore, canthaxanthin is a safe source of carotenoids for salmonid feeds.     

Horizontal gene transfer in the gut: Is it a risk?

The human gastro-intestinal microbiota involves the highest concentration of microorganisms in the human body and contains both probiotic and pathogenic bacteria. The co-presence of these different bacteria may lead to the occurrence of the so-called horizontal gene transfer (HGT) between these microorganisms. This phenomenon has been shown to allow the transfer of genes encoding virulence traits and antimicrobial drug resistance from pathogenic bacteria to other non-pathogenic strains, which highlighted its significance to human health. It could be envisaged that HGT may occur between pathogenic and probiotic bacteria in the gut, where pathogens could receive genetic elements from probiotics that enhance the pathogen’s colonization in the gut. HGT may also allow for the acquisition of virulence genes by probiotics from neighboring gut pathogens. Pertinent literature on HGT events within gut microbiota is controversial and the present paper aims to critically address this aspect. In light of an increased production of probiotics-containing foods, addressing HGT would be a vital act to ensure food safety.     

Should electrical stimulation be applied when cold shortening is not a risk?

This experiment was designed to show whether delayed high voltage stimulation (ES) is more beneficial than no stimulation (NS) to secure tenderness under circumstances where rigor conditions are difficult to control due to variations in carcass size, fatness and/or chilling capacity. Ten Charolais carcasses were split during slaughter, the left sides were stimulated at 45 min post-mortem for 45 s, and the right sides were left unstimulated. The carcass sides were then chilled at a medium chilling rate. Sarcomere length measurements confirm that there was neither cold nor heat shortening in the M. longissimus (LD). LD from ES sides aged for 2 days was more tender than non-stimulated LD (NES), although prolonged ageing eroded the advantage of ES to a non-significant advantage after 14 days. Initial tenderness differences coincided with lower 24 h calpain activity, suggesting an early onset of proteolysis and ageing (tenderisation). In contrast to conventional early ES, delayed ES, appears to be beneficial for the early development of tenderness without too much interference with enzyme. Myofibril fragment length (MFL) was a good indicator of the development of tenderness during prolonged ageing but not for the early post-mortem variation in tenderness. No colour (L*, a*, b*) differences, occurred due to stimulation treatment, while drip loss was slightly higher at 24 h post-mortem for ES meat.     

Decreasing consumers’ risk perception of food additives by knowledge enhancement in China

Food safety issues have occurred frequently in China in recent years, which results in consumers’ high risk perception of food additives. In the present research, we examined whether knowledge would decrease Chinese consumers’ risk perception of food additives under the influence of food safety issues’ risk perception; we also investigated how information selection impacted popularization effectiveness. Study 1 demonstrated that risk perception of food safety issues was positively correlated with risk perception of food additives. In addition, with increased risk perception of food safety issues, the higher level of knowledge weakened the influence of risk perception of food safety issues on risk perception of food additives. In Study 2, we proposed a consumer-risk-focused approach of knowledge popularization related to food additives, based on consumers’ cognitive rules and concerns. We compared its popularization effectiveness with the comprehensive-knowledge-based approach at three time points. We found that the consumer-risk-focused approach significantly promoted the effectiveness of popularization, including increasing knowledge accuracy and trust, and decreasing risk perception. The present study provides evidence that risk perception of food safety issues leads to biased judgments and perceptions concerning food additives, but knowledge acts as a buffering function in this biased relationship. In addition, in terms of practical application, this study contributes to improving the effectiveness of knowledge popularization about food additives.     

Modelling bacterial growth in quantitative microbiological risk assessment: is it possible?

Quantitative microbiological risk assessment (QMRA), predictive modelling and HACCP may be used as tools to increase food safety and can be integrated fruitfully for many purposes. However, when QMRA is applied for public health issues like the evaluation of the status of public health, existing predictive models may not be suited to model bacterial growth. In this context, precise quantification of risks is more important than in the context of food manufacturing alone. In this paper, the modular process risk model (MPRM) is briefly introduced as a QMRA modelling framework. This framework can be used to model the transmission of pathogens through any food pathway, by assigning one of six basic processes (modules) to each of the processing steps. Bacterial growth is one of these basic processes. For QMRA, models of bacterial growth need to be expressed in terms of probability, for example to predict the probability that a critical concentration is reached within a certain amount of time. In contrast, available predictive models are developed and validated to produce point estimates of population sizes and therefore do not fit with this requirement. Recent experience from a European risk assessment project is discussed to illustrate some of the problems that may arise when predictive growth models are used in QMRA. It is suggested that a new type of predictive models needs to be developed that incorporates modelling of variability and uncertainty in growth.     

Do free-living amoebae in treated drinking water systems present an emerging health risk?

There is an expanding body of evidence that free-living amoebae (FLA) increase both the numbers and virulence of water-based, human-pathogenic, amoeba-resisting microorganisms (ARM). Legionella spp., Mycobacterium spp., and other opportunistic human pathogens are known to be both ARM and also the etiologic agents of potentially fatal human lung infections. However, comparatively little is known about the FLA that may facilitate ARM growth in drinking water. This review examines the available literature on FLA in treated drinking water systems; in total 26 studies from 18 different countries. FLA were reported to breakthrough the water treatment barrier and enter distribution systems, in addition to the expected post-treatment system ingress. Once in the distribution system there is evidence of FLA colonization and regrowth especially in reservoirs and in-premise plumbing storage tanks. At the point of use the average FLA detection rate was 45% but highly variable (n = 16, σ = 31) due to both differences in both assay methods and the type of water systems examined. This review reveals that FLA are consistently detected in treated drinking water systems around the world and present a yet unquantified emerging health risk. However, more research is urgently required before accurate risks assessments can be undertaken to assess the impacts on human health, in households and institutions, due to exposure to FLA facilitated pathogenic ARM.     

Dietary intake of aflatoxins in the adult Malaysian population – an assessment of risk

Exposure to aflatoxins in the adult Malaysian diet was estimated by analysing aflatoxins in 236 food composites prepared as “ready for consumption”. Dietary exposure to aflatoxin B1 (AFB1) ranged from 24.3 to 34.00?ng/kg?b.w./day (lower to upper bound), with peanuts being the main contributor. Estimated liver cancer risk from this exposure was 0.61–0.85 cancers/100,000 population/year, contributing 12.4%–17.3% of the liver cancer cases. Excluding AFB1 occurrence data higher than 15?µg/kg reduced exposure by 65%–91% to 2.27–11.99?ng/kg?b.w./day, reducing the cancer risk to 0.06–0.30 cancers/100,000 population/year (contributing 1.2%–6.1% liver cancer cases). Reducing further the ML of AFB1 from 15 to 5?µg/kg yielded 3%–7% greater drop in the exposure to 0.47–10.26?ng/kg?b.w./day with an estimated risk of 0.01–0.26 cancers/100,000 population/year (0.2%–5.1% liver cancer cases attributed to dietary AFB1). These findings indicate that current MLs are adequate in protecting Malaysians’ health.     

Parvalbumin in fish skin-derived gelatin: is there a risk for fish allergic consumers?

The major allergen parvalbumin was purified from cod muscle tissues, and polyclonal antibodies were raised towards it. The antibodies were tested for specificity and an enzyme-linked immunosorbent assay (ELISA) was developed using these antibodies. The ELISA was applied to measure parvalbumin in cod skin, the starting material for fish gelatin made from deep sea, wild fish. The ELISA was sufficiently sensitive (LLOQ?=?0.8?ng?ml(-1) in extracts, corresponding to 0.02?μg of parvalbumin per g of tissue), and did not cross-react with common food constituents. Fish gelatin, wine and beer, matrices for the potential use of this ELISA, did not cause disturbance of the assay performance. The data show that the parvalbumin content in cod muscle tissue is 6.25?mg?g(-1), while the skins contained considerably less, 0.4?mg?g(-1). Washing of the skins, a common industrial procedure during the manufacturing of fish gelatin, reduced the level of parvalbumin about 1000-fold to 0.5?μg?g(-1), or 0.5?ppm. From 95 commercial lots of fish gelatin it is shown that 73 are below 0.02?μg?g(-1) parvalbumin. From the other 22 lots, the one with the highest concentration contained 0.15?μg?g(-1) of parvalbumin. These levels are generally assumed to be safe for fish-allergic individuals.     

Does simplifying transport and exposure yield reliable results? An analysis of four risk assessment methods

Four approaches for predicting the risk of chemicals to humans and fish under different scenarios were compared to investigate whether it is appropriate to simplify risk evaluations in situations where an individual is making environmentally conscious manufacturing decisions or interpreting toxics release inventory (TRI) data: (1) the relative risk method, that compares only a chemical's relative toxicity; (2) the toxicity persistence method, that considers a chemical's relative toxicity and persistence; (3) the partitioning, persistence toxicity method, that considers a chemical's equilibrium partitioning to air, land, water, and sediment, persistence in each medium, and its relative toxicity; and (4) the detailed chemical fate and toxicity method, that considers the chemical's relative toxicity, and realistic attenuation mechanisms such as advection, mass transfer and reaction in air, land, water, and sediment. In all four methods, the magnitude of the risk was estimated by comparing the risk of the chemical's release to that of a reference chemical. Three comparative scenarios were selected to evaluate the four approaches for making pollution prevention decisions: (1) evaluation of nine dry cleaning solvents, (2) evaluation of four reaction pathways to produce glycerine, and (3) comparison of risks for the chemical manufacturing and petroleum industry. In all three situations, it was concluded that ignoring or simplifying exposure calculations is not appropriate, except in cases where either the toxicity was very great or when comparing chemicals with similar fate. When the toxicity is low to moderate and comparable for chemicals, the chemicals' fate influences the results; therefore, we recommend using a detailed chemical fate and toxicity method because the fate of chemicals in the environment is assessed with consideration of more realistic attenuation mechanisms than the other three methods. In addition, our study shows that evaluating the risk associated with industrial release of chemicals (e.g., the toxics release inventory) may be misleading if only mass emissions are considered.     

Dietary advanced glycation end products--a risk to human health? A call for an interdisciplinary debate

Physiological consequences resulting from protein-bound Maillard compounds in foods must be discussed carefully. This was the idea behind the debate, which is put for discussion by the papers by Sebekova and Somoza, who argued for the motion that dietary advanced glycation end products (AGEs) are a health risk, and by Ames, who provided evidence against the motion. In this two excellent reviews, numerous arguments based on papers published in high-impact journals are given for each of the opinions. The fact that no final conclusion can be drawn, may reflect the need for a more comprehensive examination of this issue in the future. For a deeper understanding of biological consequences resulting from heated foods, the relationships between well-defined biological effects and well-characterized chemical structures must be studied. Prerequisite for this is profound chemistry--pure compounds, exact concentrations, and unambiguous analytical techniques. A real "risk assessment" is much too complex than to leave it up to one discipline alone. It must be a comprehensive and interdisciplinary approach, joining the resources of biology, medicine, and chemistry.